"In my wildest imagination I cant figure out how partial evolution of a leg might produce some kind of survival advantage whereby it would be kept by the selection process because it might be of use to the organism further down the road."
First, you began in this period to get plants invading the water margins, forming dense swamps and forests around the water's edge. And some of the fishes living in the shallows would have found it advantageous perhaps to lose the fin webbing from their fingers and develop separate digits. Fish have bony supports for the fin web. If you lose those and make the digits separate, then you can begin to grasp things and push aside the vegetation. You can also grasp the vegetation to hold your position in the water. There are quite a lot of modern fish that do this.This is from a Nova series on evolution, in this case, the creature that may come closest to providing the link between water-dwellers and land-crawlers that may be found, Acanthostega.
What we think happened is that these creatures, which were developing this mode of life in the shallows, developed legs with digits before they ever started really to walk on the land at all. So they would have got their legs first, then gradually perhaps moved into shallower and shallower watermore and more vegetation and less and less waterand eventually emerged onto the land. But it took a very long time.The show was fascinating, and the article is a very interesting read. Fins to fingers. Whoulda thunkit?
Please note the following words used in the NOVA documentary:
“What we THINK happened”, “They WOULD HAVE got their legs first”, “then gradually PERHAPS moved into shallower and shallower water”,
In every scientific discipline words like “scientists think”, “we believe”, “perhaps”, “would have”, “could have”, “might have”, “possibly”, “maybe” are used in describing the evolutionary process.
Is any of this actual science? Does any of it meet the scientific method....observable, testable, repeatable, falsifiable?
In the current “Climate Change (formerly Global Warming) debate” Scientists had the worldview that it was true and then twisted and turned the evidence to fit their worldview. The same thing has been going on in the Creation vs. Evolution debate for years.
“We know evolution is true, therefore what would have had to have happened to get from a cell in a mud puddle to a human being”?
Conjecture, conjecture, promising bit of data that might fit our worldview, more conjecture, leap of faith, unverifiable generalization, more conjecture and voila.
This then is followed by the inevitable shot across the bow of anyone who says the Emporer has no clothes. “What are you nuts? Evolution is a fact you flat earth idiot.”
Browbeat me all you want.....I believe in our Creator.
An interesting hypothesis. It would be cool if there was some scientific way to test it.